In a current network, the traffic of mobile terminals such as smartphones or future phones occupies the majority of network resources. The traffic used by the mobile terminals tends to continuously expand.
Meanwhile, for example, in accordance with services such as the Internet of Things (IoT) such as a transportation system, smart meters, and a monitoring system of devices have been developed, there is a demand to cope with the services having a variety of requirements. Thus, for example, in the next generation communication standard such as fifth generation (5G) (5G mobile communication), there is a desire for a technology that realizes higher data rate, larger capacity, and lower delay in addition to a standard technology of the fourth generation (4G) mobile communication. The next generation communication standard has been technically examined by the work group of the 3rd Generation Partnership Project (3GPP). Examples of the work group of the 3GPP include Technical Specification Group (TSG)-Radio Access Network (RAN) work group (WG) 1 and TSG-RAN WG2.
As mentioned above, in order to cope with a wide variety of services, support for many use cases is assumed in the next generation communication system such as 5G. Examples of the use case include cases classified into enhanced Mobile Broadband (eMBB), Massive Machine Type Communications (MTC), Ultra-Reliable and Low Latency Communication (URLLC).
In order to realize efficient data transmission, a Hybrid automatic repeat request (HARQ) technology has been adopted in Long Term Evolution (LTE) which is the 4G communication system. For example, in the HARQ, a reception device requests a transmission device to retransmit data which is not correctly decoded in a process of layer 1 protocol hierarchy such as LTE. In a case where the retransmission of the data is requested, the transmission device transmits retransmission data corresponding to the retransmission request for the data which is not correctly decoded in the reception device. Combination data of the data which is not correctly decoded and the retransmission data is decoded in the reception device. Accordingly, retransmission control with high efficiency and with accuracy is realized. The reception device realizes the retransmission request by respectively transmitting, to the transmission device, information of Ack in a case where the data is correctly decoded and information of Nack in a case where the data is not correctly decoded.
For example, feedback information of Ack/Nack of the LTE is transmitted with 1 bit per transmission time interval (TTI) having 14 symbols.
In 5G New Radio (NR) which is the next generation, it is agreed that the transmission of the feedback information of the Ack/Nack in units of code block Group (CBG) is introduced. The feedback information of the Ack/Nack using the CBGs is transmitted with 1 bit for each unit of CBG. For example, the number of symbols constituting the CBG and the number of symbols for transmitting the feedback information of the Ack/Nack are values which are equal to or less than 14 symbols which are the number of symbols in 1 TTI to be used in the LTE.
Incidentally, in the case of the feedback information of the Ack/Nack using the CBG, the number of bits to be used in the feedback information of Ack/Nack may increase. Thus, there is a possibility that transmission power will increase. For example, in a case where the feedback information of the Ack/Nack and other information items (for example, scheduling requests) are simultaneously transmitted, it is considered that transmission power increases as compared to a case where only the feedback information of the Ack/Nack is transmitted.
However, there are many cases that an upper limit of transmission power of a terminal is configured in advance. Thus, there is a desire to efficiently transmit information such as the feedback information of the Ack/Nack while taking account of the transmission power.
A disclosed technology has been made in view of such circumstances, and provides a terminal apparatus, a base station apparatus, a wireless communication system, and a terminal apparatus control method which efficiently transmit feedback information of Ack/Nack.
As the related arts, for example, following non patent literatures are disclosed.    NPL 1: 3GPP TS 36. 211 V14.2.0 (2017-03)    NPL 2: 3GPP TS 36. 212 V14.2.0 (2017-03)    NPL 3: 3GPP TS 36. 213 V14.2.0 (2017-03)    NPL 4: 3GPP TS 36. 300 V14.2.0 (2017-03)    NPL 5: 3GPP TS 36. 321 V14.2.0 (2017-03)    NPL 6: 3GPP TS 36. 322 V14.0.0 (2017-03)    NPL 7: 3GPP TS 36. 323 V14.2.0 (2017-03)    NPL 8: 3GPP TS 36. 331 V14.2.0 (2017-03)    NPL 9: 3GPP TS 36. 413 V14.2.0 (2017-03)    NPL 10: 3GPP TS 36. 423 V14.2.0 (2017-03)    NPL 11: 3GPP TS 36. 425 V14.0.0 (2017-03)    NPL 12: 3GPP TR 38. 801 V14.0.0 (2017-03)    NPL 13: 3GPP TR 38. 802 V14.0.0 (2017-03)    NPL 14: 3GPP TR 38. 803 V14.0.0 (2017-03)    NPL 15: 3GPP TR 38. 804 V14.0.0 (2017-03)    NPL 16: 3GPP TR 38. 900 V14.2.0 (2016-12)    NPL 17: 3GPP TR 38. 912 V14.0.0 (2017-03)    NPL 18: 3GPP TR 38. 913 V14.2.0 (2017-03)